For Graduate Assistant positions, they rarely do a real interview. It usually depends on your resume, your experience and if you know enough contacts inside the university. And this is everything I can tell about the process.
I applied through university. I interviewed at Illinois State (Normal, IL) in Apr 2023
Interview
introducing my self,,explain about difficulty situation, explain a situation where you succeded instead of having no knowledge, how would you handle your work when one of the team member is not working in your team, behavioural questions and question for them
Interview questions [1]
Question 1
explained a difficulty situation and how did you faced it?
I applied through university. I interviewed at Illinois State
Interview
Easy. Well organized interview by committee members. Questions were basic and can be answered easily. Questions were based on previous work experience, handling stress, multitasking, time management, coding experience etc.